Long-term eradication of extranodal natural killer/T-cell lymphoma, nasal type, by induced pluripotent stem cell-derived Epstein-Barr virus-specific rejuvenated T cells in vivo

Revolutionizing the treatment for nasopharyngeal cancer: the impact, challenges and strategies of stem cell and genetically engineered cell therapies

Nasopharyngeal carcinoma (NPC) is a distinct malignancy of the nasopharynx and is consistently associated with the Epstein-Barr virus (EBV) infection. Its unique anatomical location and complex aetiology often result in advanced-stage disease at first diagnosis. While radiotherapy (RT) and chemotherapy have been the mainstays of treatment, they often fail to prevent tumour recurrence and metastasis, leading to high rates of treatment failure and mortality. Recent advancement in cell-based therapies, such as chimeric antigen receptor (CAR)-T cell therapy, have shown great promise in hematological malignancies and are now being investigated for NPC. However, challenges such as targeting specific tumour antigens, limited T cell persistence and proliferation, and managing treatment-related toxicities must be addressed. Extensive research is needed to enhance the effectiveness and safety of these therapies, paving the way for their integration into standard clinical practice for better management of NPC and a better quality of life for human health.

Rejuvenated iPSC-derived GD2-directed CART Cells Harbor Robust Cytotoxicity Against Small Cell Lung Cancer

Small cell lung cancer (SCLC) is exceptionally aggressive, with limited treatment options. Disialoganglioside (GD2) is highly expressed on SCLC and is considered a good target for chimeric antigen receptor (CAR) T cells (CART). Although GD2-directed CARTs (GD2-CART) exhibit cytotoxicity against various GD2-expressing tumors, they lack significant cytotoxicity against SCLC. To enhance cytotoxicity of GD2-CARTs against SCLC, we introduced GD2-CAR into induced pluripotent stem cells (iPSC)-derived rejuvenated cytotoxic T lymphocytes (GD2-CARrejT). GD2-CARrejTs acted much more strongly against SCLC cells than did GD2-CARTs both in vitro and in vivo. Single-cell RNA sequencing elucidated that levels of expression of TIGIT were significantly lower and levels of expression of genes associated with cytotoxicity were significantly higher in GD2-CARrejTs than those in GD2-CARTs. Dual blockade of TIGIT and programmed death-1 (PD-1) increased the cytotoxicity of GD2-CARTs to some extent, suggesting that low TIGIT and PD-1 expression by GD2-CARrejTs is a major factor required for robust cytotoxicity against SCLC. Not only for robust cytotoxicity but also for availability as "off-the-shelf" T-cell therapy, iPSC-derived GD2-CARrejTs are a promising novel treatment for SCLC.

SIGNIFICANCE

This research introduces iPSC-derived rejuvenated GD2-CARTs (GD2-CARrejT) as a novel approach to combat SCLC. Compared with conventional GD2-CARTs, GD2-CARrejTs with reduced TIGIT and PD-1 expression demonstrate robust cytotoxicity against SCLC and would be a promising therapy for SCLC.

Establishment of ganglioside GD2-expressing extranodal NK/T-cell lymphoma cell line with scRNA-seq analysis

Extranodal natural killer (NK)/T-cell lymphoma, nasal type (ENKL), is characterized by Epstein-Barr virus infection and poor prognosis. We established a novel cell line, ENKL-J1, from bone marrow cells of an ENKL patient. We found that ENKL-J1 cells express the ganglioside GD2 (GD2) and that GD2-directed chimeric antigen receptor T cells exhibit cytotoxicity against ENKL-J1 cells, indicating that GD2 would be a suitable target of GD2-expressing ENKL cells. Targeted next-generation sequencing revealed TP53 and TET2 variants in ENKL-J1 cells. Furthermore, single-cell RNA sequencing in ENKL-J1 cells showed high gene-expression levels in the oncogenic signaling pathways JAK-STAT, NF-κB, and MAPK. Genes related to multidrug resistance (ABCC1), tumor suppression (ATG5, CRYBG1, FOXO3, TP53, MGA), anti-apoptosis (BCL2, BCL2L1), immune checkpoints (CD274, CD47), and epigenetic regulation (DDX3X, EZH2, HDAC2/3) also were expressed at high levels. The molecular targeting agents eprenetapopt, tazemetostat, and vorinostat efficiently induced apoptosis in ENKL-J1 cells in vitro. Furthermore, GD2-directed chimeric antigen receptor T cells showed cytotoxicity against ENKL-J1 cells in vivo. These findings not only contribute to understanding the molecular and genomic characteristics of ENKL; they also suggest new treatment options for patients with advanced or relapsed ENKL.

iPSC-derived hypoimmunogenic tissue resident memory T cells mediate robust anti-tumor activity against cervical cancer

Functionally rejuvenated human papilloma virus-specific cytotoxic T lymphocytes (HPV-rejTs) generated from induced pluripotent stem cells robustly suppress cervical cancer. However, autologous rejT generation is time consuming, leading to difficulty in treating patients with advanced cancer. Although use of allogeneic HPV-rejTs can obviate this, the major obstacle is rejection by the patient immune system. To overcome this, we develop HLA-A24&-E dual integrated HPV-rejTs after erasing HLA class I antigens. These rejTs effectively suppress recipient immune rejection while maintaining more robust cytotoxicity than original cytotoxic T lymphocytes. Single-cell RNA sequencing performed to gain deeper insights reveal that HPV-rejTs are highly enriched with tissue resident memory T cells, which enhance cytotoxicity against cervical cancer through TGFβR signaling, with increased CD103 expression. Genes associated with the immunological synapse also are upregulated, suggesting that these features promote stronger activation of T cell receptor (TCR) and increased TCR-mediated target cell death. We believe that our work will contribute to feasible "off-the-shelf" T cell therapy with robust anti-cervical cancer effects.

The Emerging Role of Induced Pluripotent Stem Cells as Adoptive Cellular Immunotherapeutics

Adoptive cell therapy (ACT) has transformed the treatment landscape for cancer and infectious disease through the investigational use of chimeric antigen receptor T-cells (CAR-Ts), tumour-infiltrating lymphocytes (TILs) and viral-specific T-cells (VSTs). Whilst these represent breakthrough treatments, there are subsets of patients who fail to respond to autologous ACT products. This is frequently due to impaired patient T-cell function or "fitness" as a consequence of prior treatments and age, and can be exacerbated by complex manufacturing protocols. Further, the manufacture of autologous, patient-specific products is time-consuming, expensive and non-standardised. Induced pluripotent stem cells (iPSCs) as an allogeneic alternative to patient-specific products can potentially overcome the issues outlined above. iPSC technology provides an unlimited source of rejuvenated iPSC-derived T-cells (T-iPSCs) or natural killer (NK) cells (NK-iPSCs), and in the context of the growing field of allogeneic ACT, iPSCs have enormous potential as a platform for generating off-the-shelf, standardised, "fit" therapeutics for patients. In this review, we evaluate current and future applications of iPSC technology in the CAR-T/NK, TIL and VST space. We discuss current and next-generation iPSC manufacturing protocols, and report on current iPSC-based adoptive therapy clinical trials to elucidate the potential of this technology as the future of ACT.

Generating hematopoietic cells from human pluripotent stem cells: approaches, progress and challenges

Human pluripotent stem cells (hPSCs) have been suggested as a potential source for the production of blood cells for clinical application. In two decades, almost all types of blood cells can be successfully generated from hPSCs through various differentiated strategies. Meanwhile, with a deeper understanding of hematopoiesis, higher efficiency of generating progenitors and precursors of blood cells from hPSCs is achieved. However, how to generate large-scale mature functional cells from hPSCs for clinical use is still difficult. In this review, we summarized recent approaches that generated both hematopoietic stem cells and mature lineage cells from hPSCs, and remarked their efficiency and mechanisms in producing mature functional cells. We also discussed the major challenges in hPSC-derived products of blood cells and provided some potential solutions. Our review summarized efficient, simple, and defined methodologies for developing good manufacturing practice standards for hPSC-derived blood cells, which will facilitate the translation of these products into the clinic.

LONRF2 is a protein quality control ubiquitin ligase whose deficiency causes late-onset neurological deficits

Protein misfolding is a major factor of neurodegenerative diseases. Post-mitotic neurons are highly susceptible to protein aggregates that are not diluted by mitosis. Therefore, post-mitotic cells may have a specific protein quality control system. Here, we show that LONRF2 is a bona fide protein quality control ubiquitin ligase induced in post-mitotic senescent cells. Under unperturbed conditions, LONRF2 is predominantly expressed in neurons. LONRF2 binds and ubiquitylates abnormally structured TDP-43 and hnRNP M1 and artificially misfolded proteins. Lonrf2-/- mice exhibit age-dependent TDP-43-mediated motor neuron (MN) degeneration and cerebellar ataxia. Mouse induced pluripotent stem cell-derived MNs lacking LONRF2 showed reduced survival, shortening of neurites and accumulation of pTDP-43 and G3BP1 after long-term culture. The shortening of neurites in MNs from patients with amyotrophic lateral sclerosis is rescued by ectopic expression of LONRF2. Our findings reveal that LONRF2 is a protein quality control ligase whose loss may contribute to MN degeneration and motor deficits.

Epstein‒Barr virus-associated cellular immunotherapy

Epstein‒Barr virus (EBV) is a human herpes virus that is saliva-transmissible and universally asymptomatic. It has been confirmed that more than 90% of the population is latently infected with EBV for life. EBV can cause a variety of related cancers, such as nasopharyngeal carcinoma, diffuse large B-cell lymphoma, and Burkitt lymphoma. Currently, many clinical studies have demonstrated that EBV-specific cytotoxic T lymphocytes and other cell therapies can be safely and effectively transfused to prevent and treat some diseases caused by EBV. This review will mainly focus on discussing EBV-specific cytotoxic T lymphocytes and will touch on therapeutic EBV vaccines and chimeric antigen receptor T-cell therapy briefly.

Antigen-specific TCR-T cells from Rag2 gene-deleted pluripotent stem cells impede solid tumour growth in a mouse model

The technology of adoptive transfer of T-cell receptor (TCR) engineered T cells is wildly investigated as it has the potential to treat solid cancers. However, the therapeutic application of TCR-T cells is hampered by the poor quality derived mainly from patients' peripheral blood, as well as heterogeneous TCRs caused by the mismatch between transgenic and endogenous TCRs. To improve the homogeneity, antigen-specificity and reduce possible autoreactivity, here we developed a technique to generate antigen-specific T cells from Rag2 gene-deleted pluripotent stem cells (PSCs) and further measured their anti-tumour efficacy. PSCs were first targeted with OT1 TCR into the Rag2 locus to prevent TCR rearrangement during T-cell development. The engineered PSCs were then differentiated through a two-step strategy, in vitro generation of haematopoietic progenitor cells, and in vivo development and maturation of TCR-T cells. Finally, the response to tumour cells was assessed in vitro and in vivo. The regenerated OT1-iT displayed monoclonal antigen-specific TCR expression, and phonotypic normalities in the spleen and lymph node tissues. Importantly, the OT1-iT cells eliminated tumour cells while releasing specific cytokines in vitro. Furthermore, adoptive transfer of OT1-iT cells suppresses solid tumour growth in tumour-bearing animals. Our study presents a novel and straightforward strategy for producing antigen-specific TCR-T cells in vivo from PSCs, allowing for allogeneic transplantation and therapy of solid tumours.

Treatment of extranodal NK/T-cell lymphoma: From past to future

Extranodal NK/T-cell lymphoma (ENKTCL) is the most common subtype of T/NK-cell lymphoma in Asia and Latin America, but very rare in North American and Europe. Patient survival has improved significantly over the past two decades. However, standard treatment has not yet been established, although dozens of prospective trials have been conducted. To help understand how the treatment of ENKTCL has evolved in the past and what trends lie ahead, we have comprehensively reviewed the treatment of this aggressive malignancy, with a particular focus on neglected or unanswered issues, such as the optimal staging method, the best partner of asparaginase (Asp), the individualized administration of Asp, the preferred sequence of CT and RT and so on. Overall, the 5-year overall survival (OS) of patients with Ann Arbor stage I/II disease increased from < 50% in the early 20th century to > 80% in recent years, and the median OS of patients with Ann Arbor stage III/IV disease increased from < 1 year to more than 3 years. The improvement in patient survival is largely attributable to advances in radiation technology and the introduction of Asp and anti-PD-1/PD-L1 immunotherapy into practice. Radiotherapy is essential for patients with early-stage disease, while Asp-based chemotherapy (CT) and PD-1/PD-L1 inhibitors significantly improved the prognosis of patients with advanced-stage disease. ENKTCL management is trending toward simpler regimens, less toxicity, and higher efficacy. Novel drugs, such as manufactured T cells, monoclonal antibodies, and small molecule inhibitors, are being intensively investigated. Based on the fact that ENKTCL is highly resistant to cytotoxic drugs except Asp, and aggressive CT leads to higher toxicity rather than better outcomes, we recommend it is unnecessary to expend additional resources to compare different combinations of Asp with cytotoxic agents. Instead, more efforts should be made to optimize the use of Asp and immunotherapy to maximize efficacy and minimize toxicity, explore ways to overcome resistance to Asp and immunotherapy, identify novel treatment targets, and define subpopulations who may benefit more from specific treatments.

Dual-antigen targeted iPSC-derived chimeric antigen receptor-T cell therapy for refractory lymphoma

We generated dual-antigen receptor (DR) T cells from induced pluripotent stem cells (iPSCs) to mitigate tumor antigen escape. These cells were engineered to express a chimeric antigen receptor (CAR) for the antigen cell surface latent membrane protein 1 (LMP1; LMP1-CAR) and a T cell receptor directed to cell surface latent membrane protein 2 (LMP2), in association with human leucocyte antigen A24, to treat therapy-refractory Epstein-Barr virus-associated lymphomas. We introduced LMP1-CAR into iPSCs derived from LMP2-specific cytotoxic T lymphocytes (CTLs) to generate rejuvenated CTLs (rejTs) active against LMP1 and LMP2, or DRrejTs. All DRrejT-treated mice survived >100 days. Furthermore, DRrejTs rejected follow-up inocula of lymphoma cells, demonstrating that DRrejTs persisted long-term. We also demonstrated that DRrejTs targeting CD19 and LMP2 antigens exhibited a robust tumor suppressive effect and conferred a clear survival advantage. Co-operative antitumor effect and in vivo persistence, with unlimited availability of DRrejT therapy, will provide powerful and sustainable T cell immunotherapy.

Advances in Allogeneic Cancer Cell Therapy and Future Perspectives on “Off-the-Shelf” T Cell Therapy Using iPSC Technology and Gene Editing

The concept of allogeneic cell therapy was first presented over 60 years ago with hematopoietic stem cell transplantation. However, complications such as graft versus host disease (GVHD) and regimen-related toxicities remained as major obstacles. To maximize the effect of graft versus leukemia, while minimizing the effect of GVHD, donor lymphocyte infusion was utilized. This idea, which was used against viral infections, postulated that adoptive transfer of virus-specific cytotoxic T lymphocytes could reconstitute specific immunity and eliminate virus infected cells and led to the idea of banking third party cytotoxic T cells (CTLs). T cell exhaustion sometimes became a problem and difficulty arose in creating robust CTLs. However, the introduction of induced pluripotent stem cells (iPSCs) lessens such problems, and by using iPSC technology, unlimited numbers of allogeneic rejuvenated CTLs with robust and proliferative cytotoxic activity can be created. Despite this revolutionary concept, several concerns still exist, such as immunorejection by recipient cells and safety issues of gene editing. In this review, we describe approaches to a feasible “off-the-shelf” therapy that can be distributed rapidly worldwide. We also offer perspectives on the future of allogeneic cell cancer immunotherapy.

Advances in Adoptive Cell Therapy Using Induced Pluripotent Stem Cell-Derived T Cells

Adoptive cell therapy (ACT) using chimeric antigen receptor (CAR) T cells holds impressive clinical outcomes especially in patients who are refractory to other kinds of therapy. However, many challenges hinder its clinical applications. For example, patients who undergo chemotherapy usually have an insufficient number of autologous T cells due to lymphopenia. Long-term ex vivo expansion can result in T cell exhaustion, which reduces the effector function. There is also a batch-to-batch variation during the manufacturing process, making it difficult to standardize and validate the cell products. In addition, the process is labor-intensive and costly. Generation of universal off-the-shelf CAR T cells, which can be broadly given to any patient, prepared in advance and ready to use, would be ideal and more cost-effective. Human induced pluripotent stem cells (iPSCs) provide a renewable source of cells that can be genetically engineered and differentiated into immune cells with enhanced anti-tumor cytotoxicity. This review describes basic knowledge of T cell biology, applications in ACT, the use of iPSCs as a new source of T cells and current differentiation strategies used to generate T cells as well as recent advances in genome engineering to produce next-generation off-the-shelf T cells with improved effector functions. We also discuss challenges in the field and future perspectives toward the final universal off-the-shelf immunotherapeutic products.

iPSC-Derived Neoantigen-Specific CTL Therapy for Ewing Sarcoma

The prognosis of Ewing sarcoma caused by EWS/FLI1 fusion is poor, especially after metastasis. Although therapy with CTLs targeted against altered EWS/FLI1 sequences at the gene break/fusion site may be effective, CTLs generated from peripheral blood are often exhausted because of continuous exposure to tumor antigens. We addressed this by generating induced pluripotent stem cell (iPSC)-derived functionally rejuvenated CTLs (rejT) directed against the neoantigen encoded by the EWS/FLI1 fusion gene. In this study, we examined the antitumor effects of EWS/FLI1-rejTs against Ewing sarcoma. The altered amino acid sequence at the break/fusion point of EWS/FLI1, when presented as a neoantigen, evokes an immune response that targets EWS/FLI1 ⁺ sarcoma. Although the frequency of generated EWS/FLI1-specific CTLs was only 0.003%, we successfully established CTL clones from a healthy donor. We established iPSCs from a EWS/FLI1-specific CTL clone and redifferentiated them into EWS/FLI1-specific rejTs. To evaluate cytotoxicity, we cocultured EWS/FLI1-rejTs with Ewing sarcoma cell lines. EWS/FLI1-rejTs rapidly and continuously suppressed the proliferation of Ewing sarcoma for >40 hours. Using a Ewing sarcoma xenograft mouse model, we verified the antitumor effect of EWS/FLI1-rejTs via imaging, and EWS/FLI1-rejTs conferred a statistically significant survival advantage. "Off-the-shelf" therapy is less destructive and disruptive than chemotherapy, and radiation is always desirable, particularly in adolescents, whom Ewing sarcoma most often affects. Thus, EWS/FLI1-rejTs targeting a Ewing sarcoma neoantigen could be a promising new therapeutic tool.

Sustainable Tumor-Suppressive Effect of iPSC-Derived Rejuvenated T Cells Targeting Cervical Cancers

Immunotherapy utilizing induced pluripotent stem cell (iPSC) technology has great potential. Functionally rejuvenated cytotoxic T lymphocytes (CTLs) can survive long-term as young memory T cells in vivo, with continuous tumor eradication. Banking of iPSCs as an unlimited “off-the-shelf” source of therapeutic T cells may be feasible. To generate safer iPSCs, we reprogrammed human papilloma virus type 16 (HPV16) E6-specific CTLs by Sendai virus vector without cotransduction of SV40 large T antigen. The iPSCs efficiently differentiated into HPV16-specific rejuvenated CTLs that demonstrated robust cytotoxicity against cervical cancer. The tumor-suppressive effect of rejuvenated CTLs was stronger and more persistent than that of original peripheral blood CTLs. These rejuvenated HPV16-specific CTLs provide a sustained tumor-suppressive effect even for epithelial cancers and constitute promising immunotherapy for cervical cancer.

Extranodal NK/T-Cell Lymphomas: The Role of Natural Killer Cells and EBV in Lymphomagenesis

Keywords: NK cells, extranodal NK/T-cell lymphoma, EBV.